Safety device for stopping elevators.



PATENTED MAY 26, 1903.

I. H. VBNN.

SAFETY DEVICE FOR STOPPING ELEVATORS.

APPLIOATION FILED SEPT. 17, 1900.

,2 SHEETS-SHEET 1.

N0 MODEL.

N'o. 729,022. PATBNTED MAY 26, 1903. r

I. H. VENN.

SAFETY DEVICE FOR STOPPING ELEVATORS.

. APPLIOATION FILED SEPT. 17, 1900. 11010921.. 2 sums-sum 2.

UNITED STATES Patented May 26, 1903.

PATENT OFFICE.

ISAAC H. VENN, OF YONKERS, NEW YORK, ASSIGNOR TO THE OTIS ELEVATOR COMPANY, JERSEY.

OF EAST ORANGE, NEW JERSEY, A CORPORATION OF NEW SAFETY DEVICE FOR STOPPING ELEVATORS.

SPECIFICATION forming part-of Letters Patent N 0. 729,022, dated May 26, 1903.

Application filed September 17, 1900. Serial No. 30,308. (No model..

To all whom it may concern:

Be it known that I, IsAAO H. VENN, a citizen of the United States, residing at Yonkers, in the county of Westchesterand State of New York, have invented certain new and useful Improvements in Safety Devices for Stopping Elevators, of which the following is a specification.

My invention relates to safety devices for 1o stopping elevators, and has for its object to provideimproved and simplified means which shall automatically stop an elevator-car if perchance it falls or runs beyond the proper or desired position.

Referring to the accompanying drawings, wherein I have illustrated embodiments of my invention sufficient to enable those skilled in the art to make and use the same, Figure 1 is a vertical part sectional view of an ele- 2o vator having one form of my safety device applied thereto. Fig. 1 is a horizontal sectional view of Fig. 1. Fig. 2 is a view similar to Fig. 1, showing another embodiment;

and Fig. 3 is a similar view of still another embodiment of the invention.

In the construction of elevators it is common to provide some sort of safety devices which shall tend to stop the elevator-car if perchance it falls or runs beyond the desired limit, and as an additional precaution it is also common to provide some sort of safety device-as, for instance, at the bottom of the well-"which shall serve to arrest the motion of the car if perchance the ordinary safety devices do not operate and the car falls or runs beyond the proper limit. I It is this latter class of safety devices to which my invention belongs; and the object, generally stated, is to provide some such safety device which shall automatically retard and eventually stop the motion of a car which is not otherwise properly controlled, as when it falls through accident or otherwise.

Generally speaking,my invention embraces two attachments constructed and operating substantially as hereinafter pointed out, one of which is arranged to move with the car and the other of which is arranged adjacent to the well or frame of the elevator, and these are adapted to mutually engage and cooperate with each other to bring the car gradually to a state of rest by taking up its momentum and acting as what may be called, broadly, a safety-brake or stopping device for the car.

With this general description I will now proceed to describe some embodiments of the invention, which will serve to explain the and use the same, and in the accompanying drawings I have not deemed it necessary to show the full operating device of an elevator, as its general construction is well understood and the particular arrangement of parts is immaterial to the purposes of my invention.

Thus, referring more particularly to Fig. 1, A represents an elevator-car connected to the usual cable A or other means for elevating and lowering it, andB B are the uprights vator car travels. Arranged adjacent to the bottom of the well and the uprights or guides of the elevator is one or more resisting or retarding devices or abutments O O, and in thisinstance each comprises a hollow cylinder 0, having a vertical groove 0, which cylinder is secured at the bottom of the well or otherwise, and mounted in this cylinder is a shaft or rod 0 adapted torotate therein, in the present instance having a step or bearing 0' at the base of the cylinder. Arranged in the periphery of this shaft or rod O is a groove or thread 0 in the form of a spiral having a gradually-decreasing pitch. Thus, it will be seen, at the top the spiral is nearly straight and the pitch or angle of spirality gradually decreases untilnear the bottom,

pitch and greater degree of spirality. Mounted on the car is one or more attachments D, which are adapted to engage the slot 0 in the cylinder O and the spiral groove 0 in the shaft or rod O as the car descends, and it will be seen that the slot 0 being vertical forms a guide for the attachment D, and the attachment entering the groove 0 of the shaft will tend to rotate the same in the cylinder. Owing to the decreasing pitch or increasing degree of spirality of the groove 0 it will be or guides in connection with which the elewhere the turns are of a largely-decreased principles thereof and enable others to make I seen that the shaft or rod will ofier an increasing resistance to the downward movement of the car with its attachment D, tending to bring it to a state of rest. The friction of the shaft rotating in the cylinder may in some instances be sufficient to accomplish the results desired, but generally it will be desirable to apply some additional resisting device, which may be of any desirable form to accomplish the purpose; but in the present instance I have shown the lower part of the shaft or rod as made in the form of a drum or sheave C and connected to this drum or sheave is a cable E, passing under and over sheaves e e and attached to a suitable Weight, (shown in the present instance in the form of a chain E,) one end of which is fixed at c It will thus be seen that as the shaft rotates the cable E is wound upon the drum or shaft, lifting the chain E, attached thereto, and offering a gradually-increasing resistance to the rotation of the shaft, and when, for instance, the caris raised the chain E will tend to rotate the shaft or rod C and restore the parts to their normal positions. The attachment D may be in various forms, and in the present instance it is shown as a bar fastened to or under the bottom of the car, with its ends projecting beyond the sides of the car in such position as to engage the slot 0 and groove 0 in the cylinders and shafts as the car descends.

Referring now to Fig. 2, there is a single cylinder 0 sunk in a pit in the well, and fitted to rotate in the upper end of the cylinder is a hollow drum or sheave 0 having an internal projection c, and connected to the sheave is a cable E and chain E or some similar resisting or retarding device. The rod or projection O in this instance is attached to the bottom of the car A in the center thereof and is provided with a groove 0 as before, but

'with the longest pitch toward the bottom, the

pitch gradually decreasing toward the top. The operation of this embodiment of the de vice will be readily understood, and as the rod or projection O descends and enters the sheave or drum the projection 0 will engage the groove 0 in the rod or projection and the drum 0 will be rotated against friction and against the additional retarding force of the chain E or other similar device connected thereto.

In Fig. 3 another embodiment of the invention is shown, comprising two curved or inclined arms or levers F F, pivoted at f and mounted on either side of the well-hole, so that their inner ends F cross each other and form a space f, the bounding-lines of said space being inclined and forming bearing edges for the attachment or projection on the car, while to their other ends F may be attached some retarding device-as, for instance, the chain Eas before, by means of the cable E. Connected to the car is a projection in the form of a roller D, so arranged that when the car descends the roller will enter the space f and bearing on the inner or adjacent edges of the levers F will force them apart, consequently drawing the lower ends against the retarding force of the chains E or other device connected therewith, and this will offer resistance to the movement of the car and bring it to a state of rest.

The constructions so far illustrated and described are ,suflicient to explain the principles of my invention, and it will be understood that it is not limited to the precise forms or constructions shown and described, as other forms or embodiments having the same general mode of operation will readily suggest themselves to those skilled in the art.

It will be seen that in all the embodiments of the invention shown there is a safety device for stopping the elevator-car comprising an attachment moving with the car, a second attachment adjacent to the well, and means whereby the degree of movement of one attachment varies inversely with the movement of the other as the car approaches the limit of travel. Thus, as shown, one of the attachments is provided with a bearing surface against which the other attachment bears, and as the car descends the degree of movement of the attachment adjacent to the well varies inversely with the downward movement of the car, it moving less when the attachments begin to engage than it does during the latter part of their engagement. So in all the embodiments shown not only will the degree of movement of one attachment vary inversely with the movement of the other as the car descends, but the retarding device (shown in the form of chains E) will increase directly with the movement of the car as it descends.

It will be seen that in all of the constructions when the car falls or otherwise reaches an abnormal position, so that the attachment moving with the car engages the fixed attachment, it will meet with opposition, and owing to the decreasing pitch or increased spirality of the groove or grooves in the shaft or shafts or the increasing angle between the levers F F the resistance will gradually increase, and this will be aided by the brake or weighted attachment connected to these parts, and this will continue until the parts reach what may be considered the angle of repose on the inclined arms or levers or in the spiral grooves, when the parts will be brought to rest and the car stopped. In other words, one of the attachments is provided with a track or bearing-surface having a Variable pitch or inclination increasing from end to end, and the other attachment engages and cooperates'therewith to allow the parts to come to the angle of repose and stop the elevator-car.

What I claim is- 1. A safety device for stopping an elevatorcar, comprising an attachment moving with the car, and a fixed attachment adjacent to the well, one of which attachments is provided with a spiral of decreasing pitch with which the other attachment is adapted to engage, substantially as described.

2. A safety device for stopping an elevatorcar, comprising an attachment moving with the car, and a fixed attachment adjacent to the well, the fixed attachment including a shaft provided with a spiral groove with which the moving attachment cooperates to stop the car, substantially as described.

3. A safety device for stopping an elevatorcar, comprising an attachment moving with the car, and a fixed attachment adjacent to the well, the fixed attachment consisting of a slotted cylinder, and a shaft within the cyl inder having a spiral groove with which groove the moving attachment cooperates to stop the car, substantially as described.

4. A safety device for stopping an elevatorcar, comprising an attachment moving with the car, and a fixed attachment adjacent to the well, one of which attachments comprises a slotted cylinder, a shaft mounted in the cylinder and having a spiral groove, a drum connected to the shaft, and a weight connected to the drum, and the other consists of a projection connected to the car engaging the slot and groove in the cylinder and shaft, substantially as described.

5. A safety device for stopping an elevatorcar, comprising an attachment moving with the car, and a second attachment arranged adjacent to the well, the construction being such substantially as described whereby the degree of movement of one attachment varies inversely with the degree of movement of the other attachment as the car approaches the limit of its downward travel.

In testimony whereof I have signed my name to this specification in the presence of 0 two subscribing witnesses.

ISAAC H. VENN.

Witnesses:

FRED SULTZER, O. H. AUSTIN. 

